The present invention relates to cannulas used to maintain an opening for elongated surgical instruments during an arthroscopic surgical procedure. More particularly the present invention relates to cannulas especially useful in orthopedic arthroscopic procedures. The present invention also relates to methods to use such aforementioned cannulas.
Athletes often place large and or repetitive stresses upon their joints and surrounding tissues. When a serious injury occurs it can often require the use of orthopedic surgery.
In the past orthopedic surgery typically required a rather large incision in the skin and underlying tissue that surrounded the injury. The amount of tissue trauma was a large factor in determining the recovery time for certain surgical operations. The amount of tissue trauma is also a large factor in determining how much pain the patient feels perioperatively.
It is highly desirable that an injured athlete be able to return to his or her athletic endeavor as soon as possible. Therefore surgical techniques to treat athletes have been developed which minimize tissue trauma and the recovery time required. One such surgical technique is arthroscopic surgery. In arthroscopic surgery a relatively small incision called a portal is made in the skin and underlying tissue. A cannula is inserted into the portal to maintain a passageway. Various elongated surgical tools or instruments such as an arthroscope, a stapler or a surgical clip applier are inserted within the cannula to perform a surgical procedure.
A human shoulder is formed by two main bones. The first bone is the upper arm or humerus. The second bone is the shoulder blade often referred to as the scapula. An end or head of the scapula, called the glenoid is joined with the humerus to create a glenohumeral cavity. The glenohumeral cavity provides a ball and socket joint. An articular cartilage covers the end of the humerus and an interface of the glenoid. The ball and socket joint is surrounded by fibrous cartilage referred to as the labrum. The two bones are joined by ligaments and a biceps tendon connects a biceps muscle to the shoulder. Four short muscles project from the scapula around the shoulder and fuse their tendons to form the rotator cuff. Surrounding the cuff is the subacromial bursa. The bursa provides a slippery surface for these tendons to move upon.
When surgically treating the shoulder with an arthroscopic technique, it is often required to surgically penetrate the bursa. However, during the surgery it is important to keep the bursa from collapsing. It is also important to note that many surgical procedures require additional portals into the shoulder independent from the portal of the cannula. When the cannula is inserted into the tissue of the shoulder, the tissue surrounding the cannula is displaced radially outward. The tissue underlying the cannula has a tendency to be pushed downward. Therefore in an arthroscopic surgical procedure, the cannula has a tendency to collapse work space. This collapse makes visualization difficult and complicates the procedure. It is desirable that a cannula would distract instead of collapse the surrounding tissue.